Silane, rubber mixture containing the silane, and vehicle tire having the rubber mixture in at least one component

ABSTRACT

The invention relates to a silane, to a rubber mixture containing the silane and to a vehicle tire comprising the rubber mixture in at least one component.The silane according to the invention has the following formula I)(R1)oSi—R2—X-A-Y—[R7—Y—]m—R7—S-G,  I)wherein according to the invention it has a spacer group between the silyl group and the S-G moiety, wherein the spacer group has an aromatic group A and at least one further aromatic group and/or an alkylene group and also the linking units X and Y, wherein the group X is selected from the groups —HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—, —HNC(═O)O—, —R3NC(═O)NR3—, —R3NC(═NR3)NR3—, —R3NC(═S)NR3—, wherein at least one R3 within the group X is a hydrogen atom, and wherein the groups Y are selected from the groups —HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—, —HNC(═O)O—, —R4NC(═O)NR4—, —R4NC(═NR4)NR4—, —R4NC(═S)NR4—, wherein at least one R4 within each group Y is a hydrogen atom, and wherein the radicals R7 are selected from aromatic groups A and alkylene radicals having 1 to 20 carbon atoms, which may have cyclic, branched and/or aliphatically unsaturated groups; and wherein G is a hydrogen atom or a —C(═O)—R8 group or a —SiR83 group, wherein R8 is selected from linear, branched and cyclic C1-C20-alkyl groups, C6-C20-aryl groups, C2-C20-alkenyl groups and C7-C20-aralkyl groups, and wherein m can take the values 0 to 4.The rubber mixture according to the invention contains at least one silane according to the invention.

The invention relates to a silane, to a rubber mixture containing thesilane and to a vehicle tire comprising the rubber mixture in at leastone component.

Silanes are known as additives for rubber mixtures, especially forvehicle tires, and in particular specifically for rubber mixturescontaining at least one silica as filler. Silanes known from the priorart are disclosed, for example, in DE 2536674 C3 and DE 2255577 C3. Thesilica in this case is attached to the polymer(s) by means of suchsilanes, the silanes as a result also being referred to as couplingagents. The attachment of the silica by means of silane coupling agentsis advantageous with respect to the rolling resistance characteristicsand processability of the rubber mixture. To this end the silanetypically has at least one sulfur moiety which takes part in thevulcanization of the rubber mixture.

In addition to the properties mentioned, however, other properties ofthe rubber mixture also play an important role, especially when beingused in vehicle tires, such as in particular the stiffness of themixture, which affects inter alia the handling characteristics of thevehicle tire.

WO 2015/172915 A1 discloses a rubber mixture comprising aurea-containing silane that has higher stiffness compared to the priorart with virtually unchanged indicators for rolling resistance and wetgrip. The urea group is present here in the spacer, that is to say thespacer group between silicon (link to the filler) and sulfur (link tothe diene rubber).

JP 2002-201312 A proposes silanes for rubber mixtures which have a ureamoiety or an acid amide and a phenylene radical in the spacer group, asa result of which improved dispersion of carbon black or silica asfillers in the rubber mixture could be achieved.

The problem addressed by the present invention is that of providing anovel silane and a rubber mixture comprising the silane, by means ofwhich a further improvement is achieved, compared to the prior art, inthe profile of properties comprising the stiffness and thus inparticular the handling predictors of the rubber mixture, in particularfor application in vehicle tires.

The problem is solved by the silane according to the invention inaccordance with claim 1, by the silica modified with the silaneaccording to the invention, by the rubber mixture according to theinvention containing the silane and also by the vehicle tire accordingto the invention and comprising the rubber mixture according to theinvention in at least one component.

The silane according to the invention has the following formula I):

(R¹)_(o)Si—R²—X-A-Y—[R⁷—Y—]_(m)—R⁷—S-G  I)

-   -   wherein o can be 1 or 2 or 3 (o is equal to 1 or 2 or 3) and the        radicals R¹ within the silyl groups (R¹)_(o)Si— may be identical        or different from each other and are selected from alkoxy groups        having 1 to 10 carbon atoms, cycloalkoxy groups having 4 to 10        carbon atoms, phenoxy groups having 6 to 20 carbon atoms, aryl        groups having 6 to 20 carbon atoms, alkyl groups having 1 to 10        carbon atoms, alkenyl groups having 2 to 20 carbon atoms,        alkynyl groups having 2 to 20 carbon atoms, aralkyl groups        having 7 to 20 carbon atoms, halides, or    -   alkyl polyether groups —O—(R⁶—O)_(r)—R⁵ wherein R⁶ are identical        or different and are branched or unbranched, saturated or        unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic        bridging C₁-C₃₀ hydrocarbon groups, preferably —CH₂—CH₂—, r is        an integer from 1 to 30, preferably 3 to 10, and R⁵ are        unsubstituted or substituted, branched or unbranched, terminal        alkyl, alkenyl, aryl or aralkyl groups, preferably —C₁₃H₂₇ alkyl        group,    -   or    -   two R¹ form a cyclic dialkoxy group having 2 to 10 carbon atoms        in which case o is <3 (o is less than 3),    -   or two or more silanes of formula I) can be bridged via radicals        R¹; and    -   wherein the radical R² is selected from the group consisting of        linear and branched alkylene groups having 1 to 20 carbon atoms,        cycloalkyl groups having 4 to 12 carbon atoms, aryl groups        having 6 to 20 carbon atoms, alkenyl groups having 2 to 20        carbon atoms, alkynyl groups having 2 to 20 carbon atoms and        aralkyl groups having 7 to 20 carbon atoms; and    -   wherein the group X is selected from the groups    -   —HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—,    -   —HNC(═O)O—, —R³NC(═O)NR³—, —R³NC(═NR³)NR³—, —R³NC(═S)NR³—,        wherein the radicals R³ within the group X may be identical or        different and are selected from a hydrogen atom or as defined        for R² under the condition that at least one R³ within the group        X is a hydrogen atom; and wherein the groups A within a molecule        may be identical or different from each other and are aromatic        groups, and    -   wherein the radicals R⁷ within a molecule may be identical or        different and are selected from aromatic groups A and alkylene        radicals having 1 to 20 carbon atoms, which may have cyclic,        branched and/or aliphatically unsaturated groups; and    -   wherein G is a hydrogen atom or a —C(═O)—R⁸ group or a —SiR⁸ ₃        group, wherein R⁸ is selected from linear, branched and cyclic        C₁-C₂₀-alkyl groups, C₆-C₂₀-aryl groups, C₂-C₂₀-alkenyl groups        and C₇-C₂₀-aralkyl groups; and    -   wherein the groups Y within a molecule may be identical or        different from each other and are selected from the groups    -   —HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—,    -   —HNC(═O)O—, —R⁴NC(═O)NR⁴—, —R⁴NC(═NR⁴)NR⁴—, —R⁴NC(═S)NR⁴—,    -   wherein the radicals R⁴ within a group Y and within a molecule        may be identical or different and are selected from a hydrogen        atom or as defined for R² under the condition that at least one        R⁴ within each group Y is a hydrogen atom; and wherein m is an        integer from 0 to 4, and wherein the silane may also be in the        form of oligomers which are formed by hydrolysis and        condensation of silanes of formula I).

In comparison to the silanes known from the prior art, the silaneaccording to the invention having the group —R²—X-A-Y—[R⁷—Y—]_(m)—R⁷—possesses a comparatively long and rigid spacer group which comprises anaromatic group A and at least one further aromatic group A and/or atleast one alkylene group and also the linking units X and Y. Theinvention thus provides a novel silane. A rubber mixture containing thesilane according to the invention has an optimized profile of propertiescomprising the stiffness, which profile could be attributed inparticular to the aromatic group A present in combination with thelinking units X and Y and the further aromatic group A and/or alkylenegroup within the spacer group. The rubber mixture according to theinvention thus exhibits a certain improvement with respect to theprofile of properties comprising handling predictors and the vehicletire according to the invention displays inter alia improved handlingcharacteristics.

The silane according to the invention and preferred embodiments thereofwill be explained hereinafter. All aspects also apply to the silane inthe rubber mixture according to the invention and in the vehicle tireaccording to the invention.

Within the context of the present invention, the terms “radical” and“group” are used synonymously in connection with chemical formulaconstituents.

As shown in formula I), the silane according to the invention is amercaptosilane (G=hydrogen atom H) or a protected (also called blocked)mercaptosilane (G=—C(═O)—R⁸ group or —SiR⁸ ₃ group).

In formula I), m can take values from 0 to 4. The moiety [R⁷—Y-] canthus in addition, where m=1, be present a further time in the molecule,where the R⁷, independently of the R⁷ indispensably present inaccordance with the formula, is an aromatic group A or, as definedhereinabove, an alkylene group. In addition, where m=2 or 3 or 4, thenumber of the aromatic groups A and/or alkylene groups can increaseaccordingly.

In a preferred embodiment of the invention, m is equal to 0, that is tosay it is preferable that m=0. Such a molecule is comparatively simpleto produce, with the presence of the essence according to the inventionof the molecule, namely the above-described combination of the aromaticgroup A with the further aromatic group A and/or the alkylene group andthe linkages X and Y in the spacer group, so that optimized stiffness inthe rubber mixture can be achieved by this alone.

As stated with regard to formula I), the group X is selected from thegroups

—HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—,

—HNC(═O)O—, —R³NC(═O)NR³—, —R³NC(═NR³)NR³—, —R³NC(═S)NR³—,wherein the radicals R³ within the group X may be identical or differentand are selected from a hydrogen atom or as defined for R² under thecondition that at least one R³ within each group X is a hydrogen atom.

The groups —HNC(═O)— and —C(═O)NH— are carboxamide groups, with the twodifferent notations being intended to express the possibleconnectivities within the molecule. It is thus conceivable that thenitrogen atom of group X in the acid amide embodiment links to thearomatic group A or to the radical R².

The groups —C(═O)O— and —OC(═O)— are ester groups, with the twonotations here also referring to the different connectivities withrespect to A and R², analogously to the acid amide groups.

The groups —OC(═O)NH— and —HNC(═O)O— are urethane groups, with the twonotations here also referring to the different connectivities withrespect to A and R², analogously to the acid amide groups.

The group —R³NC(═O)NR³— represents a urea group, where at least one ofthe radicals R³ is a hydrogen atom.

The group —R³NC(═NR³)NR³— represents a guanidine group, where at leastone of the radicals R³ is a hydrogen atom.

The group —R³NC(═S)NR³— represents a thiourea group, where at least oneof the radicals R³ is a hydrogen atom.

Preferably, each R³ of group X is a hydrogen atom.

For the case where R³ is an organic radical as defined for R², it isparticularly preferable if R³ is selected from alkyl radicals having 1to 7 carbon atoms or aromatic radicals having 6 to 10 carbon atoms, suchas for example a phenyl radical.

It is preferable for the group X to be selected from the groups—HNC(═O)—, —C(═O)NH—, —OC(═O)NH—, —HNC(═O)O—, —R³NC(═O)NR³—,—R³NC(═NR³)NR³—, —R³NC(═S)NR³—, specifically subject to the conditiongiven above for R³.

The group X is particularly preferably selected from the groups—HNC(═O)—, —C(═O)NH—, —OC(═O)NH—, —HNC(═O)O—, —R³NC(═O)NR³—, preferablyin turn from the groups —HNC(═O)—, —C(═O)NH—, —R³NC(═O)NR³—.

In a particularly advantageous embodiment of the invention, X is a ureagroup —HNC(═O)NH— where each R³=a hydrogen atom.

As stated with regard to formula I), the groups Y within a molecule maybe identical or different from each other and are selected from thegroups

—HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—,

—HNC(═O)O—, —R⁴NC(═O)NR⁴—, —R⁴NC(═NR⁴)NR⁴—, —R⁴NC(═S)NR⁴—,wherein the radicals R⁴ within a group Y and within a molecule may beidentical or different and are selected from a hydrogen atom or asdefined for R² under the condition that at least one R⁴ within eachgroup Y is a hydrogen atom.

The statements above with regard to X apply to the respective groups.

Each R⁴ is also preferably a hydrogen atom in the respective groups. Forthe case where R⁴ is an organic radical as defined for R², it isparticularly preferable if R⁴ is selected from alkyl radicals having 1to 7 carbon atoms or aromatic radicals having 6 to 10 carbon atoms, suchas for example a phenyl radical.

It is preferable for the groups Y to be selected from the groups

—HNC(═O)—, —C(═O) NH—, —OC(═O) NH—, —HNC(═O)O—, —R⁴NC(═O) NR⁴—,—R⁴NC(═NR⁴)NR⁴—, —R⁴NC(═S)NR⁴—, specifically subject to the conditiongiven above for R⁴.

The groups Y are particularly preferably selected from the groups

—HNC(═O)—, —C(═O) NH—, —OC(═O) NH—, —HNC(═O)O—, —R⁴NC(═O) NR⁴—,preferably in turn from the groups —HNC(═O)—, —C(═O)NH—, —R³NC(═O)NR³—.

In a particularly advantageous embodiment of the invention, Y is an acidamide group —HNC(═O)— or —C(═O)NH—.

Preference is given here to a connectivity that in the simple examplewhere m=0 has the following appearance:

(R¹)_(o)Si—R²—X-A-HN—C(═O)—R⁷—S-G.

According to this preferred embodiment, the nitrogen atom of the acidamide group is thus attached to the aromatic group A which links X andY.

The radicals R⁷ within a molecule may be identical or different and areselected from aromatic groups A and alkylene radicals having 1 to 20carbon atoms, which may have cyclic, branched and/or aliphaticallyunsaturated groups. For the case where R⁷ are aromatic groups A, theyare defined as the aromatic groups A described within the context of thepresent invention.

In a preferred embodiment of the invention, the radicals R⁷ are linearor branched alkylene radicals having 1 to 20 carbon atoms, preferably 1to 10 carbon atoms, particularly preferably 2 to 6 carbon atoms, orcycloalkyl groups having 4 to 8 carbon atoms.

In a particularly preferred embodiment of the invention, the radicals R⁷are alkylene groups having 2 to 4 carbon atoms, particularly preferablyhaving 2 carbon atoms, that is to say in particular ethylene groups(—CH₂—CH₂—). In particular, with m=0, the radical R⁷ is preferably analkylene group having 2 to 4 carbon atoms, particularly preferablyhaving 2 carbon atoms, that is to say in particular an ethylene group.

In a further preferred embodiment of the invention, the radicals R⁷ arearomatic groups A, in particular when m=0.

The groups A are defined and selected as below.

The groups A connect X and Y and also possibly Y and S and Y and Y, withX and Y and possibly S thus each formally also being substituents of therespective aromatic group A.

The aromatic groups A may in principle be any aromatic group, whereinthe A groups within a molecule may be identical or different from eachother. The aromatic groups A here can contain heteroatoms and/or bearsubstituents (for a respective hydrogen atom) on one or more atoms ofthe aromatic skeleton, specifically in addition to the substituents Xand Y according to the formula.

It is preferable for the aromatic groups A to be selected from the groupconsisting of phenylene, naphthylene, pyridyl, pyridazyl, pyrimidyl,pyrazyl, triazyl, quinolyl, pyrrolyl, furanyl, thiophenyl, pyrazolyl,imidazolyl, thiazolyl and oxazolyl radicals, and derivatives of thegroups mentioned.

The groups mentioned can be linked to the respective aromatic group herevia all conceivable atoms of the aromatic skeleton. In a monocyclicaromatic system having six atoms in the skeleton, such as a phenyleneradical, this means for example that the groups can be arranged in apara, meta or ortho position relative to each other.

In a particularly advantageous embodiment of the invention, the groups Aare phenylene radicals.

In a preferred embodiment of the invention, X and Y and also Y and S andalso Y and Y, for the case where m=1 to 4 and R⁷=A (aromatic group), areeach arranged in para position relative to each other on the respectivearomatic group A.

This results in an elongate and partially rigid molecular structure ofthe silane which especially in a rubber mixture can contribute to afurther increase in the stiffness thereof.

In a further preferred embodiment of the invention, X and Y and also Yand Y, for the case where m=1 to 4 and R⁷=A (aromatic group), arearranged in para position and Y and S are arranged in ortho positionrelative to each other on the respective aromatic group A.

This results in a partially rigid molecular structure of the silanewhich especially in a rubber mixture can contribute to an improvement inthe properties thereof.

The radicals R¹ of the silane according to the invention within thesilyl groups (R¹)_(o)Si— may be identical or different from each otherand are selected from alkoxy groups having 1 to 10 carbon atoms,cycloalkoxy groups having 4 to 10 carbon atoms, phenoxy groups having 6to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, alkylgroups having 1 to 10 carbon atoms, alkenyl groups having 2 to 20 carbonatoms, alkynyl groups having 2 to 20 carbon atoms, aralkyl groups having7 to 20 carbon atoms, halides, or

alkyl polyether groups —O—(R⁶—O)_(r)—R⁵ wherein R⁶ are identical ordifferent and are branched or unbranched, saturated or unsaturated,aliphatic, aromatic or mixed aliphatic/aromatic bridging C₁-C₃₀hydrocarbon groups, preferably —CH₂—CH₂—, r is an integer from 1 to 30,preferably 3 to 10, and R⁵ are unsubstituted or substituted, branched orunbranched, terminal alkyl, alkenyl, aryl or aralkyl groups, preferably—C₁₃H₂₇ alkyl group,ortwo R¹ form a cyclic dialkoxy group having 2 to 10 carbon atoms in whichcase o is <3 (o is less than three),or two or more silanes of formula I) can be bridged via radicals R¹.

All of the recited radicals R¹ and linkages may be combined with oneanother within a silyl group.

Where two silanes of formula I) are bridged to one other, they share aradical R¹. It is also possible for more than two silanes to be linkedto one another in this way. Following the synthesis of the silane offormula I), it is therefore conceivable for two silanes of formula I) tobe bridged to each other via the radicals R¹. It is also possible formore than two silanes to be linked to one another in this way, such asfor example via dialkoxy groups.

The silane according to the invention may also comprise oligomers whichare formed by hydrolysis and condensation of silanes of the formula I).This firstly encompasses oligomers of two or more silanes of formula I).According to the invention, secondly this also encompasses oligomerswhich are formed by condensation of at least one silane of formula I)with at least one further silane which does not correspond to formulaI). The “further silane” may in particular be silane coupling agentsknown to those skilled in the art.

The silane of formula I) preferably comprises, in each silyl group(R′)_(o)Si—, at least one radical R¹ which can serve as a leaving group,such as in particular alkoxy groups or any other of the mentioned groupsthat are bonded by an oxygen atom to the silicon atom, or halides.

The radicals R¹ preferably comprise alkyl groups having 1 to 6 carbonatoms or alkoxy groups having 1 to 6 carbon atoms, or halides,particularly preferably alkoxy groups having 1 to 6 carbon atoms.

In a particularly advantageous embodiment of the invention, the radicalsR¹ within a silyl group (R¹)_(o)Si— are identical and are alkoxy groupshaving 1 or 2 carbon atoms, that is to say methoxy groups or ethoxygroups, very particularly preferably ethoxy groups, where o=3 (o isequal to three).

However, including in the case of oligomers or if two R¹ form a dialkoxygroup, the remaining radicals R¹ are preferably alkyl groups having 1 to6 carbon atoms or halides or alkoxy groups having 1 to 6 carbon atoms,preferably 1 or 2 carbon atoms, that is to say methoxy groups or ethoxygroups, very particularly preferably ethoxy groups.

The radical R² of the silane according to the invention is selected fromthe group consisting of linear and branched alkylene groups having 1 to20 carbon atoms, cycloalkyl groups having 4 to 12 carbon atoms, arylgroups having 6 to 20 carbon atoms, alkenyl groups having 2 to 20 carbonatoms, alkynyl groups having 2 to 20 carbon atoms and aralkyl groupshaving 7 to 20 carbon atoms.

It is preferable for the radical R² to be a linear or branched alkylenegroup having 2 to 8 carbon atoms or a cycloalkyl group having 4 to 8carbon atoms, such as in particular a cyclohexyl radical.

In a particularly advantageous embodiment of the invention, R² is analkylene radical having 2 to 6 carbon atoms, preferably 2 to 4 carbonatoms, especially preferably 2 or 3 carbon atoms, with a propyleneradical having 3 carbon atoms being very particularly preferred.

In a particularly preferred and exemplary embodiment of the invention,the silane according to the invention has the following formula II):

In this case, with regard to formula I), m=0, all instances of R¹ areethoxy groups, R² is a propylene radical, X is a urea group, R⁷=A andboth instances of A are phenylene radicals, wherein all linkages arearranged in para position and Y is an acid amide group the nitrogen atomof which is linked onto the respective phenylene radical in thedirection of the urea group (X).

The moiety —S-G represents, as described above, a mercapto group, thatis to say —S—H, or a blocked mercapto group, that is to say for example—S—C(═O)—R⁸ or —S—SiR⁸ ₃.

R⁸ is selected from linear, branched and cyclic C₁-C₂₀ alkyl groups,C₆-C₂₀-aryl groups, C₂-C₂₀-alkenyl groups and C₇-C₂₀-aralkyl groups.Here, a radical R⁸ may also comprise any desired combination of linear,branched and/or cyclic constituents.

The silane of formula II) represents a preferred example according tothe invention. A particularly good profile of properties comprising thestiffness of the rubber mixture according to the invention is achievedwith this. The latter also has improved properties with respect to thehandling indicators.

In this case G is particularly preferably an alkanoyl group having atotal of 1 to 10 carbon atoms.

In a preferred embodiment of the invention, G=H, that is to say ahydrogen atom.

In a further preferred embodiment of the invention, G is a —C(═O)—R⁸group, with R⁸ particularly preferably being a C₁-C₂₀alkyl group; G isthus in this case preferably an alkanoyl group.

In an advantageous embodiment, the alkanoyl group has a total of 1 to10, in particular 7 to 10 carbon atoms.

In a particularly preferred and exemplary embodiment of the invention,the silane according to the invention has the following formula III):

In this case, with regard to formula I), m=0, all instances of R¹ areethoxy groups, R² is a propylene radical, X is a urea group, R⁷=A andboth instances of A are phenylene radicals, wherein all linkages arearranged in para position and Y is an acid amide group the nitrogen atomof which is linked onto the respective phenylene radical in thedirection of the urea group (X), and G is an octanoyl radical, that isto say an octanoyl protecting group.

In a further preferred and exemplary embodiment of the invention, R⁷ isa linear alkylene radical, preferably having 2 to 6 carbon atoms.

In a further preferred and exemplary embodiment of the invention, R⁷ isa linear alkylene radical, preferably having 2 to 6 carbon atoms, and Gis an alkanoyl group, preferably having 2 to 10 carbon atoms.

In a further preferred and exemplary embodiment of the invention, thesilane according to the invention has the following formula VIII):

In this case, with regard to formula I), m=0, all instances of R¹ areethoxy groups, R² is a propylene radical, X is a urea group, R⁷ is anethylene radical and A is a phenylene radical, wherein the linkages arearranged in para position and Y is an acid amide group, and G is anacetyl radical, that is to say an acetyl protecting group.

The rubber mixture according to the invention contains at least onesilane according to the invention. It is in principle conceivable forthe rubber mixture to contain a mixture of a plurality of silanesaccording to the invention from different embodiments, that is to saypossibly with different groups X, Y, A, R⁷ and G and also R¹, R²,possibly R³ and R⁴, different linkages to the aromatic groups A and alsowith different values for m. The rubber mixture can in particular alsocontain a mixture of two or more silanes I), II), III) or VIII). Therubber mixture can also contain the silane according to the invention ofillustrated formulae I) to III) and/or VIII) in combination with othersilanes known in the prior art, possibly as oligomers, as describedhereinabove.

Such coupling agents known from the prior art are in particular and byway of example bifunctional organosilanes having at least one alkoxy,cycloalkoxy or phenoxy group as a leaving group on the silicon atom andhaving as another functionality a group which, possibly after cleavage,can enter into a chemical reaction with the double bonds of the polymer.The latter group may for example be the following chemical groups:

—SCN, —SH, —NH₂ or -Sx- (with x=2 to 8)

For example, silane coupling agents used may be3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane or3,3′-bis(triethoxysilylpropyl) polysulfides having 2 to 8 sulfur atoms,such as for example 3,3′-bis(triethoxysilylpropyl) tetrasulfide (TESPT),the corresponding disulfide (TESPD), or else mixtures of the sulfideshaving 1 to 8 sulfur atoms with different contents of the varioussulfides. TESPT may for example also be added as a mixture with carbonblack (trade name X50S® from Evonik).

The prior art also discloses a silane mixture which contains 40% to 100%by weight of disulfides, particularly preferably 55% to 85% by weight ofdisulfides and very particularly preferably 60% to 80% by weight ofdisulfides. Such a mixture is obtainable for example from Evonik underthe trade name Si 266® which is described in DE 102006004062 A1 forexample.

Blocked mercaptosilanes as known for example from WO 99/09036 may alsobe used as a silane coupling agent. Silanes as are described in WO2008/083241 A1, WO 2008/083242 A1, WO 2008/083243 A1 and WO 2008/083244A1 can also be used. Usable silanes are for example those marketed underthe name NXT (e.g. 3-(octanoylthio)-1-propyltriethoxysilane) in a numberof variants by Momentive, USA, or those marketed under the name VP Si363® by Evonik Industries.

In a particularly advantageous embodiment of the invention, the rubbermixture contains the silane of formula III).

The rubber mixture according to the invention is preferably a rubbermixture which is suitable for use in vehicle tires and for this purposepreferably contains at least one diene rubber.

Diene rubbers are rubbers which are formed by polymerization orcopolymerization of dienes and/or cycloalkenes and thus have C═C doublebonds either in the main chain or in the side groups.

The diene rubber is selected here from the group consisting of naturalpolyisoprene and/or synthetic polyisoprene and/or epoxidizedpolyisoprene and/or butadiene rubber and/or butadiene-isoprene rubberand/or solution-polymerized styrene-butadiene rubber and/oremulsion-polymerized styrene-butadiene rubber and/or styrene-isoprenerubber and/or liquid rubbers having a molecular weight M_(w) of greaterthan 20 000 g/mol and/or halobutyl rubber and/or polynorbornene and/orisoprene-isobutylene copolymer and/or ethylene-propylene-diene rubberand/or nitrile rubber and/or chloroprene rubber and/or acrylate rubberand/or fluoro rubber and/or silicone rubber and/or polysulfide rubberand/or epichlorohydrin rubber and/or styrene-isoprene-butadieneterpolymer and/or hydrogenated acrylonitrile-butadiene rubber and/orhydrogenated styrene-butadiene rubber.

Nitrile rubber, hydrogenated acrylonitrile-butadiene rubber, chloroprenerubber, butyl rubber, halobutyl rubber or ethylene-propylene-dienerubber in particular are used in the production of technical rubberarticles, such as belts, drive belts and hoses, and/or footwear soles.

Preferably, the diene rubber is selected from the group consisting ofnatural polyisoprene and/or synthetic polyisoprene and/or butadienerubber and/or solution-polymerized styrene-butadiene rubber and/oremulsion-polymerized styrene-butadiene rubber.

In a preferred development of the invention, at least two differenttypes of diene rubber are used in the rubber mixture.

The rubber mixture according to the invention preferably contains atleast one silica as filler, by way of which the advantages of the silaneaccording to the invention emerge in particular.

The terms “silicic acid” and “silica” are used synonymously in thecontext of the present invention.

The silicas may be silicas known to those skilled in the art which aresuitable as fillers for tire rubber mixtures. However, particularpreference is given to using a finely divided, precipitated silica whichhas a nitrogen surface area (BET surface area) (in accordance with DINISO 9277 and DIN 66132) of 35 to 400 m²/g, preferably of 35 to 350 m²/g,particularly preferably of 100 to 320 m²/g and very particularlypreferably of 100 to 235 m²/g, and a CTAB surface area (in accordancewith ASTM D 3765) of 30 to 400 m²/g, preferably of 30 to 330 m²/g,particularly preferably of 95 to 300 m²/g and very particularlypreferably of 95 to 200 m²/g.

Such silicas result, for example in rubber mixtures for inner tirecomponents, in particularly good physical properties of thevulcanizates. Advantages in mixture processing by way of a reduction inmixing time can also result here while retaining the same productproperties, leading to improved productivity. Examples of silicas thatcan be used thus include not only those of the Ultrasil® VN3 (tradename) type from Evonik but also silicas having a comparatively low BETsurface area (such as for example Zeosil® 1115 or Zeosil® 1085 fromSolvay) and highly dispersible silicas, so-called HD silicas (forexample Zeosil® 1165 MP from Solvay).

The amount of the at least one silica here is preferably 5 to 300 phr,particularly preferably 10 to 200 phr, very particularly preferably 20to 180 phr. In the case of different silicas, the indicated amounts meanthe total amount of silicas present.

The indication “phr” (parts per hundred parts of rubber by weight) usedin this document is the conventional indication of quantity for mixturerecipes in the rubber industry. The dosage of the parts by weight of theindividual substances is based in this document on 100 parts by weightof the total mass of all high molecular weight (Mw greater than 20 000g/mol) and hence solid rubbers present in the mixture.

The indication “phf” (parts per hundred parts of filler by weight) usedin this document is the conventional indication of quantity for couplingagents for fillers in the rubber industry. In the context of the presentapplication, phf relates to the silica present, meaning that any otherfillers present, such as carbon black, are not included in thecalculation of the amount of silane.

The rubber mixture according to the invention preferably contains atleast one silane of formula I), preferably at least the silane offormula II) and/or formula III) and/or formula VIII) in an amount offrom 1 to 25 phr and in the preferred case with silica as fillerpreferably 2 to 20 phf.

The silane(s) according to the invention are preferably added during theproduction of the rubber mixture according to the invention in at leastone base-mixing stage which preferably contains at least one dienerubber and preferably at least one silica as filler.

The present invention thus further provides a process for producing therubber mixture according to the invention, wherein at least one silaneaccording to the invention as described above is added preferably in atleast one base-mixing stage.

In an advantageous embodiment of the invention, the at least one silaneaccording to the invention is adsorbed onto silica beforehand and inthis form is mixed into the rubber mixture.

In the process according to the invention for producing the rubbermixture according to the invention, it is therefore preferable if the atleast one silane according to the invention is adsorbed onto silicabeforehand and in this form is mixed into the rubber mixture.

The present invention further provides a silica which has been modifiedat least on its surface with at least one silane according to theinvention.

By way of example, the modification is effected by at least thefollowing process steps:

-   -   a) dissolving the silane according to the invention in an        organic solvent;    -   b) bringing at least one silica into contact with the solution        from step a) and then stirring the resulting suspension,        preferably for 30 minutes to 18 hours;    -   c) drying the modified silica obtained.

The rubber base mixture containing at least one silane according to theinvention and/or one silica according to the invention is subsequentlyprocessed to give a finished rubber mixture by adding vulcanizationchemicals, see below in particular a sulfur vulcanization system, andthen vulcanized, to obtain a vulcanizate according to the invention ofthe rubber mixture according to the invention.

The rubber mixture according to the invention can contain carbon blackas a further filler, specifically preferably in amounts of 2 to 200 phr,particularly preferably 2 to 70 phr.

The rubber mixture according to the invention may contain furtherfillers, preferably in minimal amounts, i.e. preferably 0 to 3 phr.Within the context of the present invention, the further(non-reinforcing) fillers include aluminosilicates, kaolin, chalk,starch, magnesium oxide, titanium dioxide, or rubber gels and alsofibers (such as for example aramid fibers, glass fibers, carbon fibers,cellulose fibers).

Further, optionally reinforcing, fillers are for example carbonnanotubes ((CNTs), including discrete CNTs, so-called hollow carbonfibers (HCF) and modified CNTs containing one or more functional groupssuch as hydroxy, carboxy and carbonyl groups), graphite and graphene andwhat is known as “carbon-silica dual-phase filler”.

In the context of the present invention zinc oxide is not included amongthe fillers.

The rubber mixture can further contain customary additives in customaryparts by weight which during the production of said mixture are addedpreferably in at least one base-mixing stage. These additives include

a) aging stabilizers, such as for exampleN-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD),N,N′-diphenyl-p-phenylenediamine (DPPD), N,N′-ditolyl-p-phenylenediamine(DTPD), N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD),2,2,4-trimethyl-1,2-dihydroquinoline (TMQ),b) activators, such as for example zinc oxide and fatty acids (e.g.stearic acid) and/or other activators, such as zinc complexes, such asfor example zinc ethylhexanoate,c) antiozonant waxes,d) resins, especially tackifying resins for inner tire components,e) masticating aids, such as for example 2,2′-dibenzamidodiphenyldisulfide (DBD), andf) processing aids, such as in particular fatty acid esters and metalsoaps, such as for example zinc soaps and/or calcium soaps,g) plasticizers, such as in particular aromatic, naphthenic orparaffinic mineral oil plasticizers, such as for example MES (mildextraction solvate) or RAE (residual aromatic extract) or TDAE (treateddistillate aromatic extract), or rubber-to-liquid (RTL) oils orbiomass-to-liquid (BTL) oils, preferably having a content of polycyclicaromatics of less than 3% by weight according to method IP 346 ortriglycerides, such as for example rapeseed oil, or factices orhydrocarbon resins or liquid polymers, the mean molecular weight ofwhich (determination by GPC=gel permeation chromatography, using amethod based on BS ISO 11344:2004) is between 500 and 20000 g/mol, withmineral oils being particularly preferred as plasticizers.

When using mineral oil this is preferably selected from the groupconsisting of DAE (distillate aromatic extracts) and/or RAE (residualaromatic extract) and/or TDAE (treated distillate aromatic extracts)and/or MES (mild extracted solvents) and/or naphthenic oils.

The total amount of further additives is 3 to 150 phr, preferably 3 to100 phr and particularly preferably 5 to 80 phr.

Zinc oxide (ZnO) may be included in the total proportion of furtheradditives in the abovementioned amounts.

This may be any type of zinc oxide known to those skilled in the art,such as for example ZnO granules or powder. The zinc oxideconventionally used generally has a BET surface area of less than 10m²/g. However, it is also possible to use a zinc oxide having a BETsurface area of 10 to 100 m²/g, for example so-called “nano zincoxides”.

The vulcanization of the rubber mixture according to the invention ispreferably conducted in the presence of sulfur and/or sulfur donors withthe aid of vulcanization accelerators, it being possible for somevulcanization accelerators to act simultaneously as sulfur donors. Theaccelerator is selected from the group consisting of thiazoleaccelerators and/or mercapto accelerators and/or sulfenamideaccelerators and/or thiocarbamate accelerators and/or thiuramaccelerators and/or thiophosphate accelerators and/or thioureaaccelerators and/or xanthogenate accelerators and/or guanidineaccelerators.

Preference is given to using a sulfenamide accelerator selected from thegroup consisting of N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and/orN,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS) and/orbenzothiazyl-2-sulfenomorpholide (MBS) and/orN-tert-butyl-2-benzothiazylsulfenamide (TBBS) or a guanidine acceleratorsuch as diphenylguanidine (DPG).

The sulfur donor substances used may be any sulfur donor substancesknown to those skilled in the art. If the rubber mixture contains asulfur donor substance, the latter is preferably selected from the groupcomprising for example thiuram disulfides, such as for exampletetrabenzylthiuram disulfide (TBzTD) and/or tetramethylthiuram disulfide(TMTD) and/or tetraethylthiuram disulfide (TETD) and/or thiuramtetrasulfides, such as for example dipentamethylenethiuram tetrasulfide(DPTT), and/or dithiophosphates, such as for example

DipDis (bis(diisopropyl)thiophosphoryl disulfide) and/orbis(O,O-2-ethylhexylthiophosphoryl) polysulfide (e.g. Rhenocure SDT 50®,Rheinchemie GmbH) and/or zinc dichloryldithiophosphate (e.g. RhenocureZDT/S®, Rheinchemie GmbH) and/or zinc alkyldithiophosphate, and/or1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane and/or diarylpolysulfides and/or dialkyl polysulfides.

Further network-forming systems such as can be obtained for exampleunder the trade names

Vulkuren®, Duralink® or Perkalink®, or network-forming systems such asare described in WO 2010/049216 A2, can also be used in the rubbermixture. This system contains a vulcanizing agent which crosslinks witha functionality of greater than four and at least one vulcanizationaccelerator.

It is particularly preferable to use the accelerators TBBS and/or CBSand/or diphenylguanidine (DPG).

Vulcanization retarders may also be present in the rubber mixture.

The terms “vulcanized” and “crosslinked” are used synonymously in thecontext of the present invention.

In a preferred development of the invention, a plurality of acceleratorsare added in the final mixing stage during the production of thesulfur-crosslinkable rubber mixture.

The sulfur-crosslinkable rubber mixture according to the invention isproduced by the process that is customary in the rubber industry, inwhich in one or more mixing stages a base mixture comprising allconstituents except for the vulcanization system (sulfur andvulcanization-influencing substances) is firstly produced. The finishedmixture is produced by adding the vulcanization system in a final mixingstage. The finished mixture is for example processed further and broughtinto the appropriate shape by means of an extrusion operation orcalendering.

This is followed by further processing by vulcanization, wherein sulfurcrosslinking takes place due to the vulcanization system added withinthe context of the present invention.

The above-described rubber mixture according to the invention isparticularly suitable for use in vehicle tires, especially pneumaticvehicle tires. Application in all tire components is in principleconceivable here, in particular in a tread, especially in the cap of atread of cap/base construction.

The cap here is the part of the tread of the vehicle tire that comesinto contact with the driving surface, while the base is the inner partof the tread that is located radially beneath the cap and does not comeinto contact with the driving surface.

For use in vehicle tires, the mixture, as a finished mixture prior tovulcanization, is preferably brought into the shape of a tread and isapplied in the known manner during production of the green vehicle tire.

The production of the rubber mixture according to the invention, for useas a sidewall or other body mixture in vehicle tires, is effected as hasalready been described. The difference lies in the shaping after theextrusion operation/the calendering of the mixture. The shapes thusobtained of the as-yet unvulcanized rubber mixture for one or moredifferent body mixtures then serve for the construction of a green tire.

“Body mixture” refers here to the rubber mixtures for the innercomponents of a tire, such as essentially squeegee, inner liner (innerlayer), core profile, belt, shoulder, belt profile, carcass, beadreinforcement, bead profile, flange profile and bandage. The as-yetunvulcanized green tire is subsequently vulcanized.

For use of the rubber mixture according to the invention in drive beltsand other belts, especially in conveyor belts, the extruded, as-yetunvulcanized mixture is brought into the appropriate shape and oftenprovided at the same time or subsequently with strength members, forexample synthetic fibers or steel cords. This usually affords amulti-ply construction consisting of one and/or more plies of rubbermixture, one and/or more plies of identical and/or different strengthmembers and one and/or more further plies of the same and/or anotherrubber mixture.

The present invention further provides a vehicle tire comprising therubber mixture according to the invention containing at least one silaneaccording to the invention in at least one component.

The vulcanized vehicle tire in at least one component comprises avulcanizate of at least one rubber mixture according to the invention.It is known to those skilled in the art that most substances, such asfor example the rubbers and silanes present, in particular the silaneaccording to the invention, are present in chemically modified formeither already after mixing or only after vulcanization.

Within the context of the present invention, “vehicle tires” are to beunderstood to mean pneumatic vehicle tires and solid rubber tires,including tires for industrial and construction site vehicles, truck,car and two-wheeled-vehicle tires.

The vehicle tire according to the invention preferably comprises therubber mixture according to the invention at least in the tread.

The vehicle tire according to the invention preferably comprises therubber mixture according to the invention at least in the sidewall.

The rubber mixture according to the invention is further also suitablefor other components of vehicle tires, such as for example in particularthe flange profile, and also for inner tire components. The rubbermixture according to the invention is further also suitable for othertechnical rubber articles, such as bellows, conveyor belts, air springs,belts, drive belts or hoses, and also footwear soles.

The invention shall be explained in more detail hereinbelow withreference to exemplary embodiments.

The silane of formula III), as an example according to the invention,was prepared in the following way:

1. Preparation of 1-(4′-aminophenyl)-3-(3-(triethoxysilyl)propyl)ureaAccording to the Synthesis Scheme of formula IV)

3-(Isocyanatopropyl)triethoxysilane (11.44 ml, 11.44 g, 46.2 mmol, 1.0eq.) was added dropwise at room temperature (RT) to a solution ofpara-phenylenediamine (10.00 g, 92.5 mmol, 2.0 eq.) in dichloromethane(300 ml of DCM). After stirring overnight, the solvent was removed on arotary evaporator, affording a gray solid (21.57 g) as the crudeproduct.

Purification by column chromatography was performed in a plurality ofsmall portions of approx. 3-4 g each (approx. 74% by weight yield ineach case) on silica gel (DCM/ethanol 9:1).

After drying under high vacuum, the target compound was isolated in theform of a light gray solid (extrapolated for the total product: 15.96 g,44.9 mmol, 97% based on silane).

¹H NMR (nuclear magnetic resonance) (500 MHz, DMSO-d₆) δ 7.82 (s, 1H),6.98 (d, J=8.7 Hz, 2H), 6.45 (d, J=8.7 Hz, 2H), 5.91 (t, J=5.8 Hz, 1H),4.66 (s, 2H), 3.74 (q, J=7.0 Hz, 6H), 3.00 (q, J=6.8 Hz, 2H), 1.48-1.39(m, 2H), 1.14 (t, J=7.0 Hz, 9H), 0.57-0.49 (m, 2H).

¹³C NMR (126 MHz, DMSO-d₆) δ 155.69, 143.33, 129.62, 120.22, 114.12,57.70, 41.81, 23.49, 18.24, 7.25.

2. Preparation of 4-(octanoylthio)benzoic Acid According to theSynthesis Scheme of Formula V)

Octanoyl chloride (1.7 ml, 1.63 g, 10.0 mmol, 1.0 eq.) was addeddropwise at RT to a solution of 4-mercaptobenzoic acid (1.54 g, 10.0mmol, 1.0 eq.) and pyridine (5.0 ml, 4.91 g, 62.1 mmol, 6.2 eq.) in THF(15 ml; tetrahydrofuran).

The resulting suspension was stirred overnight at RT and subsequentlypoured onto ice in order to remove the pyridinium salt and precipitateout the target molecule. The reaction mixture was stirred for 30 min.

The resulting light brown precipitate was filtered off using a Buchnerfunnel and washed with cold demineralized water (2×50 ml).

After drying under high vacuum, the target compound was isolated in theform of a light brown powder (1.38 g, 4.9 mmol, 49%).

Melting point: 170° C.

¹H NMR (500 MHz, DMSO-d₆) δ 14.10 (s, 1H), 8.89 (d, J=8.0 Hz, 2H), 8.44(d, J=7.9 Hz, 2H), 3.62 (t, J=7.4 Hz, 2H), 2.04-2.27 (m, 8H), 1.75 (t,J=6.6 Hz, 3H).

¹³C NMR (126 MHz, DMSO-d₆) δ 195.88, 166.77, 134.24, 132.90, 131.47,129.95, 43.30, 31.12, 28.38, 28.21, 25.00, 22.09, 13.99.

ESI-MS (electrospray ionization mass spectrometry) m/z (%): 281.12[M+H]+(100), 303.10 [M+Na]+(73), 583.21 [2M+Na]+(59).

3. Preparation of 4-(octanoylthio)benzoyl chloride (In Situ) Accordingto the Synthesis Scheme of Formula VI)

DMF (0.1 ml, 1.3 mmol) was added to a suspension of4-(octanoylthio)benzoic acid (0.84 g, 3.0 mmol, 1.0 eq.) in THF (20 ml).Oxalyl chloride (1.3 ml, 1.91 g, 15.0 mmol, 5.0 eq.) was added dropwiseto the reaction mixture at 0° C. and the mixture was stirred for 30 minat this temperature.

The resulting yellow solution was then stirred for a further 3 h at RT.Thereafter, the solvent and excess oxalyl chloride were removed by meansof a high vacuum and cold trap.

A yellow solid was isolated that was used for the next synthesis stepwithout further analysis or purification (on account of its reactivity).

4. Preparation of the Silane of Formula III) According to the SynthesisScheme of Formula VII)

A solution of 4-(octanoylthio)benzoyl chloride (0.90 g, 3.0 mmol, 1.0eq.) in THF (10 ml) was added dropwise at RT, over a period of 15 min,to a solution of 1-(4′-aminophenyl)-3-(3″-(triethoxysilyl)propyl)urea(1.07 g, 3.0 mmol, 1.0 eq.) and triethylamine (2.1 ml, 1.52 g, 15.0mmol, 5.0 eq.) in THF (10 ml).

The resulting white suspension was stirred overnight at RT and thenfiltered off using a Buchner funnel. The filter cake was washed withcold THF (2×50 ml) and demineralized water (4×50 ml). The powderobtained after drying was resuspended in water for 30 min in order toremove ammonium salts still present.

After drying under high vacuum, the target compound was isolated in theform of a white powder (1.45 g, 2.3 mmol, 78% yield).

Melting point: 158° C.

¹H NMR (500 MHz, DMSO-d₆) δ 10.23 (s, 1H), 8.37 (s, 1H), 7.95-8.02 (m,2H), 7.58-7.64 (m, 2H), 7.52-7.57 (m, 2H), 7.33-7.39 (m, 2H), 6.14 (t,J=5.7 Hz, 1H), 3.75 (q, J=7.0 Hz, 6H), 3.05 (q, J=6.6 Hz, 2H), 2.74 (t,J=7.4 Hz, 2H), 1.57-1.65 (m, 2H), 1.48 (ddd, J=10.8, 5.2, 2.8 Hz, 2H),1.21-1.34 (m, 8H), 1.15 (t, J=7.0 Hz, 9H), 0.83-0.89 (m, 3H), 0.51-0.59(m, 2H).

¹³C NMR (126 MHz, DMSO-d₆) δ 196.18, 164.35, 155.23, 136.76, 135.86,134.14, 132.48, 131.01, 128.37, 121.08, 117.73, 57.75, 43.26, 41.80,31.12, 28.38, 28.22, 25.02, 23.42, 22.09, 18.28, 13.99, 7.29.

²⁹Si NMR (99 MHz, DMSO-d₆) 5-44.56.

ESI-MS m/z (%): 618.30 [M+H]+(100), 640.28 [M+Na]+(18).

The silane of formula VIII), as a further example according to theinvention, is prepared for example in the following way:

1. Preparation of 3-(acetylthio)propionic Acid According to theSynthesis Scheme of Formula IX)

This introduces a thioacetyl group by nucleophilic substitution of3-chloropropionic acid with potassium thioacetate (KSAc) and DMF(dimethylformamide) as solvent.

2. Preparation of 3-(acetylthio)propionyl chloride (In Situ) Accordingto the Synthesis Scheme of Formula X)

This activates the acid functionality with oxalyl chloride (COCl)₂ andcatalytic amounts of DMF in THF as solvent.

3. Preparation of 1-(4′-aminophenyl)-3-(3-(triethoxysilyl)propyl)ureaAccording to the Synthesis Scheme of Formula XI)

This forms the urea by reaction of para-phenylenediamine and oneequivalent of 3-(isocyanatopropyl)triethoxysilane in DCM(dichloromethane) as solvent.

4. Preparation of the Silane of Formula VIII) According to the SynthesisScheme of Formula XII)

This forms the amide by reaction of 3-(acetylthio)propionyl chloridewith 1-(4′-aminophenyl)-3-(3″-triethoxysilyl)propyl)urea in the presenceof triethylamine as auxiliary base and THF as solvent.

The silane of formula VIII) can also be prepared by starting from3-chloropropionyl chloride and converting it to the amide with1-(4′-aminophenyl)-3-(3″-triethoxysilyl)propyl)urea and only thenintroducing the thioacetyl group by nucleophilic substitution of thechloride (with potassium thioacetate).

The prepared silane of formula III) and/or VIII) is mixed into a rubbermixture according to the invention containing at least one diene rubberand at least one silica as filler. To this end, the silane of formulaIII) and/or VIII) is preferably adsorbed onto a silica beforehand andsubsequently added in this form to the rubber mixture.

Adsorption onto silica is carried out, for example, as follows:

To a suspension of silica, for example granulated silica, in DMF isadded, at room temperature, a solution of the silane of formula III)and/or VIII) dissolved in DMF in the desired silica/silane ratio. Forexample, 30.0 g of silica (VN3, Evonik) and 4.43 g of the silane offormula III) or 3.32 g of the silane of formula VIII) are used.

The resulting suspension is for example stirred overnight at 120° C. andthe solvent is subsequently removed under reduced pressure. After dryingfor one day under high vacuum at 40° C., the modified silica thusobtained is comminuted by means of a mortar possibly according to thefineness desired. It is then for example dried under high vacuum for afurther day at 40° C.

The rubber mixture according to the invention is by way of exampleapplied in the form of a preformed tread of a vehicle tire (as describedabove) to a green tire and subsequently vulcanized with the latter.

1.-15. (canceled)
 16. A silane of formula I):(R¹)_(o)Si—R²—X-A-Y—[R⁷—Y—]_(m)—R⁷—S-G,  I) wherein o can be 1, 2 or 3;and, the radicals R¹ within the silyl groups (R¹)_(o)Si— are identicalor different from each other and are selected from alkoxy groups having1 to 10 carbon atoms, cycloalkoxy groups having 4 to 10 carbon atoms,phenoxy groups having 6 to 20 carbon atoms, aryl groups having 6 to 20carbon atoms, alkyl groups having 1 to 10 carbon atoms, alkenyl groupshaving 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms,aralkyl groups having 7 to 20 carbon atoms, halides, or the radicals R¹are alkyl polyether groups —O—(R⁶—O)_(r)—R⁵ wherein R⁶ are identical ordifferent and are branched or unbranched, saturated or unsaturated,aliphatic, aromatic or mixed aliphatic/aromatic bridging C₁-C₃₀hydrocarbon groups, preferably —CH₂—CH₂—, r is an integer from 1 to 30,preferably 3 to 10, and R⁵ are unsubstituted or substituted, branched orunbranched, terminal alkyl, alkenyl, aryl or aralkyl groups, preferably—C₁₃H₂₇ alkyl group, or two R¹ form a cyclic dialkoxy group having 2 to10 carbon atoms in which case o is <3, or two or more silanes of formulaI) can be bridged via radicals R¹; and wherein the radical R² isselected from the group consisting of linear and branched alkylenegroups having 1 to 20 carbon atoms, cycloalkyl groups having 4 to 12carbon atoms, aryl groups having 6 to 20 carbon atoms, alkenyl groupshaving 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atomsand aralkyl groups having 7 to 20 carbon atoms; and wherein the group Xis selected from the groups —HNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—,—OC(═O)NH—, —HNC(═O)O—, —R³NC(═O)NR³—, —R³NC(═NR³)NR³—, —R³NC(═S)NR³—,wherein the radicals R³ within the group X may be identical or differentand are selected from a hydrogen atom or as defined for R² under thecondition that at least one R³ within the group X is a hydrogen atom;and wherein the groups A within a molecule may be identical or differentfrom each other and are aromatic groups; and wherein the radicals R⁷within a molecule may be identical or different and are selected fromaromatic groups A and alkylene radicals having 1 to 20 carbon atoms,which may have cyclic, branched and/or aliphatically unsaturated groups;and wherein G is a hydrogen atom or a —C(═O)—R⁸ group or a —SiR⁸ ₃group, wherein R⁸ is selected from linear, branched and cyclicC₁-C₂₀-alkyl groups, C₆-C₂₀-aryl groups, C₂-C₂₀-alkenyl groups andC₇-C₂₀-aralkyl groups; and wherein the groups Y within a molecule may beidentical or different from each other and are selected from the groupsHNC(═O)—, —C(═O)NH—, —C(═O)O—, —OC(═O)—, —OC(═O)NH—, —HNC(═O)O—,—R⁴NC(═O)NR⁴—, —R⁴NC(═NR⁴)NR⁴—, —R⁴NC(═S)NR⁴—, wherein the radicals R⁴within a group Y and within a molecule may be identical or different andare selected from a hydrogen atom or as defined for R² under thecondition that at least one R⁴ within each group Y is a hydrogen atom;and wherein m is an integer from 0 to 4, and wherein the silane may alsobe in the form of oligomers which are formed by hydrolysis andcondensation of silanes of formula I).
 17. The silane as claimed inclaim 16, wherein m=0.
 18. The silane as claimed in claim 16, wherein Xis selected from the group consisting of: —HNC(═O)—, —C(═O)NH—,—OC(═O)NH—, —HNC(═O)O—, —R³NC(═O)NR³—, —R³NC(═NR³)NR³—, and—R³NC(═S)NR³—.
 19. The silane as claimed in claim 16, wherein Y isselected from the group consisting of: —HNC(═O)—, —C(═O)NH—, —OC(═O)NH—,—HNC(═O)O—, —R⁴NC(═O)NR⁴—, —R⁴NC(═NR⁴)NR⁴—, and —R⁴NC(═S)NR⁴—.
 20. Thesilane as claimed in claim 16, wherein the radicals R⁷ are linear orbranched alkylene radicals having 1 to 20 carbon atoms, preferably 1 to10 carbon atoms, particularly preferably 2 to 6 carbon atoms, orcycloalkyl groups having 4 to 8 carbon atoms.
 21. The silane as claimedin claim 16, wherein the radicals R⁷ are aromatic groups A.
 22. Thesilane as claimed in claim 16, wherein A is selected from the groupconsisting of phenylene, naphthylene, pyridyl, pyridazyl, pyrimidyl,pyrazyl, triazyl, quinolyl, pyrrolyl, furanyl, thiophenyl, pyrazolyl,imidazolyl, thiazolyl and oxazolyl radicals, and derivatives of thegroups thereof.
 23. The silane as claimed in claim 16 having formulaII):


24. The silane as claimed in claim 16 having formula III):


25. The silane as claimed in claim 16, wherein the radicals R⁷ are alinear alkylene radical, preferably having 2 to 6 carbon atoms.
 26. Thesilane as claimed in claim 16, wherein the radicals R⁷ are a linearalkylene radical, preferably having 2 to 6 carbon atoms, and G is analkanoyl group, preferably having 2 to 10 carbon atoms.
 27. The silaneas claimed in claim 16 having formula VIII):


28. The silane as claimed in claim 16 further comprised on the surfaceof silica.
 29. The silane as claimed in claim 28 further comprised in arubber mixture.
 30. The silane as claimed in claim 29 further comprisedin at least one component of a vehicle tire.